Phytoplankton refers to the group of minute, autotrophic organisms that
float in the water surface of rivers, lakes and oceans. Like any terrestrial plants,
phytoplankton requires sunlight, water and nutrients for growth. Sunlight is most
abundant near the water surface where phytoplankton remains. They acquire
their food reserves from the fixation of carbon dioxide with the presence of light
and built up within the protoplasm (Relon, 1988). Thus, organism occupying
higher tropic level may both directly and indirectly dependent for energy supply.
Aside from its important role in the food chain, phytoplankton performs vital role
in the biogeochemical cycles necessary for biological metabolism.
Plankters are capable of adapting to different environmental conditions
and their distribution are affected by several factors such as pH, temperature,
light intensity and carbon dioxide concentration (Jorgensen, 1996). Moreover,
they need a wide variety of chemical elements but the two critical are nitrogen
and phosphorus, which are used to make proteins, nucleic acids and other cell
parts. Hence, the presence of elements in the water allows the phytoplankton to
survive and reproduce. The population of phytoplankton is said to be sensitive to
fluctuations in the environment. Temperature affects the uptake of carbon dioxide
for photosynthesis and oxygen for respiration. As temperature reaches beyond
optimal range, net carbon dioxide changes until the limits are reached and refer
to the hot and cold limits of net photosynthesis (Salisbury and Ross, 1992).
Furthermore, extreme temperature may also inhibit subsequent photosynthesis
at optimal temperature.
Another condition that affects the growth of phytoplankton is
eutrophication, which rejuvenated by an increase in plant nutrients. This would
allow algae bloom on the surface that prevents penetration of light in the lake
water (Round, 1981). Eutrophication leads to oxygen depletion thus, death of
In recent times, Sampaloc Lake shows the sign of being eutrophic
because the lake is extremely threatened by diverse human activities (i.e. illegal
settlement along the shores, resulting pollution illegal fish-pens, overfeeding and
crowded fish cages). The overuse of commercial fish feeding may resulted in
high nitrogen levels, low dissolved oxygen and proliferation of water lilies that
made the lake on its current trophic condition.
Recently, the local government of San Pablo regulates the construction of
fish cages within the lake. According to Mrs. Aleiga (personal communication)
one family can only avail 10 x 10 m2
of fish cages to support their personal needs
and other necessesities. It is in this premise that characterization of the
phytoplankton community be done in Sampaloc Lake. This would verify the
current trophic status of the lake by identifying indicator species present in the
Objectives of the Study
The main objective of this research is to determine the structural diversity
of the phytoplankton in Sampaloc Lake, San Pablo City, Laguna.
Specifically, this study aims to:
1. identify and classify the phytoplankton present;
2. compare the phytoplankton diversity in each station ; and
3. assess the diversity of phytoplankton in the study site.
Significance of the Study
This study dealt with the adoption of the different ecological parameters to
determine the community structure and dynamics of phytoplankton present in
Sampaloc Lake. The phytoplankton collection at different areas of the lake would
increase the value of knowledge on their distributional data. Such data are
essential in any phytoplankton studies by describing its structure as well as
diversity. Furthermore, such data generated by describing species richness and
structural adaptations are very useful in any attempt to various conservation
Since phytoplankton depends upon certain conditions for growth, they are
good indicators of change in their environment (Herring, 2010). For these
reasons, phytoplankton are the primary interest to oceanographers and Earth
scientists around the world because they can relate the distribution of
phytoplankton on the climate (Herring, 2010). Moreover, data derived from the
physico-chemical parameters of this study will enhance the knowledge of the
local government of San Pablo City by knowing the diversity of the phytoplankton
in the lake and how these organisms can affect their daily life. This information
would help them to create sustainable management planning for maintenance of
This study is also useful for the student who wishes to study freshwater
biology and are interested in algae. This would help them to identify common
phytoplankton that is present in freshwater ecosystem that would give them a
detailed description as well as their ecological importance.
Scope and Limitations
This study was limited in determining the community structure of
phytoplankton present in Sampaloc Lake located at San Pablo City, Laguna,
Philippines. Classification and identification of the collected phytoplankters were
based using Patrick and Reimer (1966) and Prescott (1951) keys. Identification
was done to the lowest possible level. The species distribution and its ecological
importance were discussed.
Phytoplankton investigation was done last November 21, 2010 from 11:00
a.m. to 3:00 p.m. This time was appropriate for sampling since phytoplankton is
dependent upon the amount of sunlight.
Moreover, the only physico- chemical parameters measured were
temperature, pH, transparency and dissolved oxygen concentration.
REVIEW OF LITERATURE
Taxonomy and Distribution of Phytoplankton
The factors affecting the distribution and growth of the freshwater
phytoplankton are a complex of physical (light, temperature, viscosity, current,
velocity, and turbidity), chemical (nitrate, phosphate, silicate, organic factors) and
biological features (growth rate, interaction, grazing etc.) The gross correlation
between nutrient status and organic production suggests that nutrients are a
limiting factor particularly in tropical and semi-tropical regions (Round, 1973).
Abundant freshwaters organisms are greatly dominated in
Euglenophyceae and Chlorophyceae which are the blue green algae and green
algae. There are 450 species in genus Chlamydomanas that found in freshwater
lakes and ponds but only few in marine waters (Willen and Willen, 1955).
The taxonomy of the phytoplankton of Balayan Bay was studied by a
group of undergraduate students from De la Salle University (de la Cruz et al,
1992) and reported a total of 104 species of phytoplankton collected and found
out that the dominant species were the following: Bacteriastrum, Chaetoceros
In the succeeding year, Relon (1988) did the taxonomy of phytoplankton in
the Northwestern Luzon. Her study included collections from Pagudpud, Ilocos
Norte up to Balayan Bay in Batangas. She reported 108 species belonging to 39
genera and 19 families. She also noted a significant difference in the number of
cell counts in both seasons of the year and correlated some physico-chemical
factors such as temperature, salinity, pH, nitrates and phosphates affecting the
distribution of phytoplankton.
In freshwater environment the desmid are strictly confined because this
group is rich in species of genus Cosmarium ( Willen and Willen, 1955).
Ecological Factors Influencing Growth of Phytoplankton
Turbidity caused by suspended matter such as clay, silt, and organic
matter and by plankton and other microscopic organisms can interfere with the
passage of light through the water (Andersson, 2003). Thus, turbidity measures
the cloudiness of water- the cloudier the water, the greater the turbidity.
Patrick and Reimer (1966) emphasized that the amount of incident light
does not seem to be the limiting factor for growth, but rather the turbidity of water
caused by turbulence. The magnitude of turbidity depends on the amount and
grain size of suspended matter. They added that turbidity return sediments
previously deposited on the bottom into suspension.
The light-photosynthetic relationship was affected by temperature
(Prescott, 1968) and other factors such as salinity and nutrient concentration.
Since most of the incident light energy was transformed into heat, temperature
conditions were usually dependent on the light regime.
With respect to light intensity, photosynthetic pigments were the most
affected part. In diatoms, cells growing at higher light intensities have a lower
chlorophyll concentration per cell and a higher maximum photosynthetic rate
(Strickland and Parsons, 1972). Diatoms continue to synthesize their
photosynthetic pigments when growing heterotrophically in the dark and were
capable of photosynthesis immediately upon return to the light.
In a study made by Frouin and Iacobellis, they argue that the impact of
phytoplankton extends beyond its warming influence. Changes in Earth's surface
reflection caused by increases or decreases in phytoplankton concentrations
may significantly affect the interactions of the planet's climate system with
human-produced concentrations of greenhouse gases and aerosols. They also
argue that the climatological significance of phytoplankton increased or
decreased from region to region, since the magnitude of phytoplankton
concentrations ultimately will dictate the strength of their warming influence.
In fishponds, turbidity reduces phytoplankton growth thus reducing fish
production (Larsson, 1994). He added that erosion carries silt, sand and other
materials into ponds where they settle and lead to filling in of the pond. This
shortens the lifespan of the pond, creating problems with macrophytes, thus,
reducing the productive volume and sometimes increases turbidity.
Global warming has great influence on the growth and distribution of
phytoplankton; light and nutrients are also greatly affected by changes in the
environment (Behrenfeld ,2006).
According to Piat (2007), they had recently discovered that the basic
chemistry of the ocean was being altered by excess carbon dioxide absorption,
which threatens organisms by increasing acidification. Acidification was caused
by a reaction between CO2 and H2O, which forms carbonic acid (H2CO3).
Carbonic acid increases the acidity of waters by lowering the pH.
With increasing acidity, every species that constructs skeletons and shells
of CaCO3 will find it more difficult to survive in the future. The impact of such a
widespread decline in shell-producing marine organisms could be disastrous for
nearly all-aquatic ecosystems. Increasing acidity will also affect numerous
reproductive and/or physiological processes in other species with unknown
The pH of freshwater ecosystems can fluctuate considerably within daily
and seasonal timeframes, and most freshwater animals have evolved to tolerate
a relatively wide environmental pH range. Animals can become stressed or die
when exposed to pH extremes or when pH changes rapidly, even if the change
occurs within a pH range that is normally tolerated (Tucker and D’Abramo,
Temperature influences oxygen solubility, photosynthetic rates, respiration
and metabolism (Wetzel, 1983). It has a significant influence on the species of
fish that can be cultured, growth rates, the quality of fish flesh, food conversion
efficiency, and the economics of a fish culture operation.
In addition, the temperature of air and water has great influence in the
growth and distribution of phytoplankton as they constantly change e.g. they
change as tides and currents bring new water into the area, or as solar radiation
heats up surface layers.
Temperature affects the uptake of carbon dioxide for photosynthesis and
the uptake of oxygen for respiration. As temperature increases or decreases
beyond the optimal range, net carbon dioxide becomes steadily smaller until
finally limits are reached where CO2 equals to intake. Those limits are the hot
and cold limits of net photosynthesis, respectively (Salisbury and Ross, 1992).
Furthermore, extreme temperature may also inhibit subsequent photosynthesis
at optimal temperature.
If the top layer of the water warms, it makes harder for the upwelling of
nutrients to reach the surface, starving the phytoplankton. Researchers found
that drops in the amount of chlorophyll as detected by the satellite closely
corresponded to increases in surface water temperature, confirming the
predictions of climate models (Brahic, 2006).
In the Philippines, surface temperatures warm during summer and cool
during the rainy season. As reflected in the temperature readings furnished by
PAGASA, temperature of the water changed as the season changes.
Nutrient Uptake and Growth
The size of phytoplankton will be reflected in the relationship between
maximum specific rates of nutrient uptake and growth. Maximum nutrient uptake
rates are typically higher than the maximum growth rates and steady. State
growth rates are independent of nutrients concentration in chemostat cultures
Assimilated nitrate can be stored (as nitrate, ammonia or low molecular
weight organic compound)and utilized for growth at some future time (Antia et. al
1963) have shown theoretically that such intracellular nutrient reserves can have
a marked influence on the relative abundance of phytoplankton species in a
variable nutrient environment. Lags between uptake and growth make possible
higher growth rates than could otherwise occur (Caperon, 1969).
McCarthy and Goldman (1979) present evidence that small-scale variation
in nutrient supply allow phytoplankton to grow at nearly maximum rates when
nutrient concentration are undetectable. Cells with the capacity to store nitrogen
when nitrogen supply exceeds the demand by growth should have advantage in
a variable nutrient environment over cell that have smaller storage capacities
(Lawas and Caperon 1976).
Many phytoplankton species posses a large vacuole within which nitrogen
reserves could be compartmentalized (Eppley and Coastworth 1968).This
organelle is esp. characteristics of large dinoflagellates and diatoms its volume
increasing as cell volume increases (Smayda 1965 and Paasche 1973). The
vacuole comprises of 30-90% of the cell volume in diatoms with mean spherical
diameters greater than 5um (Smayda, 1970).
An ability to store nutrients would provide a mechanism by which large cell
could grow faster than small cells under non steady state condition.
Phosphate and Nitrogen: Major source of Nutrients
In addition to carbon, oxygen and hydrogen that plants can find directly
from water, and carbon dioxide in the atmosphere, two major nutrients are
necessary for the development of aquatic life: Nitrogen (N) and phosphorus (P).
A third one, silica (Si), is necessary for the development of diatoms. During
eutrophication, the concentration of nutrients in the water changes. In some
cases one out of the three nutrients may be totally bound to the aquatic life and
will not be available for further growth of algae. This nutrient is then called the
limiting factor. The ratio of nitrogen to phosphorus compounds in a water body is
an important factor determining which of the two elements will be the limiting
factor, and consequently which one has to be controlled in order to reduce a
bloom (Volterra, 2002).
Generally, phosphorus tends to be the limiting factor for phytoplankton in
fresh waters. Intermediate areas such as river plumes are often phosphorus-
limited during spring, but may turn to silica or nitrogen limitation in summer.
When phosphorus is the limiting factor, a phosphate concentration of 0.01 mg l-1
is enough to support plankton and concentrations from 0.03 to 0.1 mg l-1 or
higher will be likely to promote blooms but may turn to silica or nitrogen limitation
in summer. When phosphorus is the limiting factor, a phosphate concentration of
0.01 mg l-1 is enough to support plankton and concentrations from 0.03 to 0.1
mg l-1 or higher will be likely to promote blooms (Volterra, 2002).
Consequences of Eutrophication
The major consequence of eutrophication concerns the availability of
oxygen. Plants, through photosynthesis, produce oxygen in daylight. On the
contrary, in darkness all animals and plants, as well as aerobic microorganisms
and decomposing dead organisms, respire and consume oxygen. These two
competitive processes are dependent on the development of the biomass. In the
case of severe biomass accumulation, the process of oxidation of the organic
matter that has formed into sediment at the bottom of the water body will
consume all the available oxygen. Even the oxygen contained in sulphates will
be used by some specific bacteria. This will lead to the release of sulphur that will
immediately capture the free oxygen still present in the upper layers. Thus, the
water body will loose all its oxygen and all life will disappear (Boualam, 2002).
In parallel with these changes in oxygen concentration other changes in
the water environment occur changes in algal population during eutrophication,
macroalgae, phytoplankton (diatoms, dinoflagellates, chlorophytes) and
cyanobacteria, which depend upon nutrients, light, temperature and water
movement, will experience excessive growth (Boualam, 2002).
Ecosystem experience changes in zooplankton, fish and shellfish
population when eutrophication occurs. Being most sensitive to oxygen
availability, these species may die from oxygen limitation or from changes in the
chemical composition of the water such as the excessive alkalinity that occurs
during intense photosynthesis. Ammonia toxicity in fish for example is much
higher in alkaline waters (Volterra, 2002).
Effects of Eutrophication
Lake eutrophication is now a world-wide concern. The main manifestation
of this process is a very strong development of primary producers in the euphotic
zone and very low oxygen concentration in deep layers of the lake. In highly
eutrophic lake, phytoplankton is often dominated by cyanobacteria (Yasser Abdul
Kader Al-Gahwari, 2007). These organisms form water blooms at the surface
which strongly reduce light penetration in the water column most cyanobacteria
species are toxic, their massive development compromise drinking water
production and leisure activities (Yasser Abdul Kader Al-Gahwari, 2007).
Cyanobacteria have been largely studied in fresh water systems, due to their
ability to proliferate, to form massive surface scums, and to produce toxins that
have been implicated in animal or human poisoning.
Algae display varying degrees of complexity depending on the
organization of their cells. Macroalgae, phytoplankton and cyanobacteria may
colonize marine, brackish or fresh waters wherever conditions of light,
temperature and nutrients are favourable. There is growing evidence that
nutrients, especially nitrogen, favour the duration and frequency of such
toxic“blooms”, and concentrations of toxin in the cells
A. Description of the Study Site
Sampaloc Lake was located within the city proper of San Pablo, Laguna
(Appendix A) with an area of 104 hectares, a maximum depth of 27 meters and a
maximum width of 1.2 kilometers. Generally, Sampaloc Lake has muddy
substrate. The lake was situated at latitude of 14.079°N and 121.33°E
During the sampling, the lake was divided into two (2) zones namely
littoral and limnetic zone. The littoral zone was subdivided into four (4) stations
(Figure 1) and designated as (1) commercial, (2) residential and fish cages, (3)
tributary and (4) non-residential area. The various environmental conditions were
the bases of assigning different stations of the lake. This include as having the
presence of household’s waste, the milieu of having plants, along the fish cage
and the natural environment of the lake.
B. Environmental Parameters
The following physico-chemical parameters were determined in this study
namely transparency, temperature, pH and dissolved oxygen.
Figure 1. Shows the different station and their points. Red Dots- Point 1, Yellow Dots- Point
2, Green Dots- Point 3. The large number indicates the station for the water
sampling both for Limnetic and Littoral zone (Map Source:
+ 21 14°4.477 N 121°19.608
+ 16 14°4.577 N 121°19.528
+ 14 14°4.882 N 121°19.483
+ 16 14°4.805 N 121°19.542
+ 16 14°4.911 N 121°19.716
+ 19 14°4.988 N 121°19.904+ 22 14°4.701 N 121°20.132+ 16 14°4.548 N 121°20.096
+ 15 14°4.781 N 121°20.186
+ 14 14°4.441 N 121°19.993+ 19 14°4.382 N 121°19.815+ 16 14°4.419 N 121°19.699+ 12 14°4.744 N 121°19.631+ 16 14°4.799 N 121°19.574
+ 11 14°4.493 N 121°19.540
Figure 2. The different stations for water sampling for both littoral and limnetic zone in Sampaloc Lake, San Pablo
Laguna. (A)Station 1-Commercial Area, (B)Station 2- Residential (C) Fish Cages Area, (D)Station 3-
Tributary Area, (E)Station 4- Non Residential Area and (F) Station 5- Limnetic Area.
A circular metallic plate known as Secchi Disc was used having a
10 cm radius. The disc was lowered into the water and the distance of its
first disappearance was noted. The plate was slowly raised and the
distance when the plate reappeared was taken. The average distance
(cm) between the two readings represented the turbidity of the water. The
procedure was repeated three times in each station.
B.2 Temperature and pH
Temperature and pH were measured using Oakton pH tester 30.
The probe was immersed in water for at least two (2) minutes before
measurement was noted and repeated for three (3) times.
B.3 Dissolved Oxygen (DO) Concentration
Dissolved Oxygen (DO) concentration was measured at each
sampling site using the Oakton DO 300 series. The probe was immersed
at about six (6) inches below the water surface and performed three (3)
times, which the average measurement was noted.
C. Collection and Preservation of Specimens
Collections of samples were done using horizontal hauling for littoral zone
and vertical hauling for limnetic zone. There were three (3) points considered for
each sampling station. The water samples were collected by using plankton net,
which has a diameter of 15 cm and height of 44 cm. In littoral zone, the collection
of sample was done by throwing the net at about 5 meters and repeated for five
(5) times. On the other hand, vertical hauling was used in limnetic zone. This was
done by submerging the plankton net at 10 meters below the water surface. The
collected water sample was transferred to 100 mL collecting bottle that was
previously labeled with station identification and replicate number.
Water samples were preserved in 4% buffered formalin (Appendix C). The
buffered formalin was used as a preservative that prevents deformation of the
cell (Azanza – Corrales et al, 1993).
Identification of preserved samples was based on the keys used by
Patrick and Reimer (1966) and Prescott (1951).
D. Assessment of Phytoplankton Community
D.1 Enumeration of Phytoplankton
In order to calculate the density of phytoplankton present in water
sample, a counting chamber and a microscope were used for this purpose. Since
the size of the phytoplankton were small, haemocytometer was used (Neubauer
Brand) as suggested by Martinez (1975).
One hundred (100) milliliter water samples were concentrated to 10 mL
and 1 mL aliquot was taken and carefully placed in the trough of the
haemocytometer. The organisms were observed under low and high
magnifications of the microscope for identification and enumeration.
The filled chamber was allowed to stand 1-2 minutes prior to counting in
order to give enough time for cells to settle down. Observation follows under low
magnification to check the distribution of the cells within the chamber.
The haemocytometer comprises 5 quadrants and each quadrant consists
of 16 squares. Large squares were used to count the phytoplankton present in
the chamber to show the average organism present.
Cambridge Microscope was used in order to examine the features of each
specimen under LPO and HPO. Ocular Micrometer was also used to measure
the length and width of each species. Each of the measurement (length and
width) was multiplied by 0.255µm (HPO) and 1.02µm (LPO) to calculate the size
of the specimen. Above measurement were calibrated to get the definite size of
Abundance is the number of species in an area. It was used to determine
the abundance of the species on a particular environment and also used to
calculate the number of species per cell present in the lake. In determining the
species abundance in each sampling station the following formula was used
Density= N X V1
N= Number of cell in 1 mL sample
V1= Total Volume of the sample where 1 ml aliquot taken (mL)
Vs= Volume of the water filtered by plankton net within a hauling
E. Community Structure
To asses the estimation of species diversity, dominance, richness and
evenness of phytoplankton present in the study site, different diversity indices
were used.Dominance is defined as the number of species that can be found in
an area in frequent occurrence (Odum, 1980). Moreover, Shannon index as well
as Simpson’s index emphasizes not only the number of species (richness or
variety) but also the apportionment of the numbers of individuals among the
species (Odum, 1971 and Reish, 1984). Evenness, therefore, takes into
consideration the dominance or lack of dominance of one or a few organisms in
the community. Lastly, Margalef’s is the number of different species in a given
area. It was used in conservation studies to determine the sensitivity of
ecosystems and their resident species.
All the calculations to characterize the phytoplankton community was
evaluated using the software Paleontological Statistics ver. 1.88.
RESULTS AND DISCUSSIONS
Physical parameters of the lake water
The different environmental parameters measured in five stations of
Sampaloc Lake during November 2010 were summarized in Table 1. Water
temperature ranges from 25.86°C to 28.23°C with a mean of 27.33 ± 0.24°C.
Surface water varied from pH 8.27 to 8.43 generating a mean value of
8.35±0.05. On the other hand, the measured water transparency were 20.08
in to 38.58 in giving a mean of 30.38 ± 1.568 in while dissolved oxygen
concentration ranged from 8.75 mg/L to 10.22 mg/L with a mean of 9.33 ±
Table 1. Physico-chemical Parameters of Sampaloc lake (November 2010).
*values are reported as mean ± Standard Error (s/√n)
*values with the same letters are not significantly different at α= 0.05
*values in parentheses are acceptable ranges for a healthy aquatic ecosystem
Parameters Station Average
1 2 3 4 5
The highest temperature was obtained in Station 1 (28.23°C) and the
lowest temperature was observed in Station 4 (25.86°C) during the
sampling period. There was no significant differences (α0.05< 0.91)
observed from among the five stations of the lake. Each station would
imply different degree of stresses hence variation can be observed. Mean
temperature of the lake has a value of 27.33 ± 0.24°C, which may
maintain the development and production of phytoplankton present in the
lake. The optimum temperature that enabled the phytoplankton to grow is
C to 320
C (Boney, 1971).
The temperature of a freshwater environment can directly affect the
environment as a whole and the organism that occupy it. Phytoplankton
as a photosynthetic organism can proceed their production even if the
temperature rises up to 31 ºC (Boney, 1971). The condition that most
blue-green algae seem to flourish is having warm water temperatures at
During the sampling period the pH of surface water in Sampaloc Lake
ranges from 8.27 ±0.09 to 8.43 ±0.05. The highest pH value was obtained in
station 3 (pH=8.43 ±0.05) while lowest at station 5 (pH=8.27±0.09). The ideal
pH of culture condition is 6.5 - 9.0 while about pH 8.0 in natural condition
(Relon, 1988). Data showed that the surface water of Sampaloc Lake is
slightly basic (mean=8.35±0.05), which is better for phytoplankton
development (Relon, 1988).
Stations 4 showed significant differences in pH at stations 3
(α0.05>0.030) and station 4 (α0.05>0.013). The differences in pH for each
station can be attributed to the presence of fish cages wherein Station 3
had fewer fish cages as compared to station 4 and station 5. By the
presence of the fish cages, it has been recently discovered that water
altered by excess carbon dioxide absorption, threatens organisms by
increasing acidification. Acidification will tend to be higher because of the
reaction of water and the carbon dioxide (CO2) released by the fish.
Carbon dioxide dissolves slightly in water to form a weak acid called
carbonic acid (H2CO3). After that, carbonic acid reacts slightly and
reversibly in water to form hydronium cation, H3O+, and the bicarbonate
ion, HCO3- (Shakhashir, 2008). pH of water will tend to be alkaline by
having relatively low concentration of hydrogen ion. This condition is
favorable for the growth and respiration uptake of phytoplankton (Moss,
The highest measurement of transparency was recorded in station 2
with 38.58+5.26 in (3.22 ft) and the lowest measurement was observed in
station 5 with 20.08+4.19 in (1.67 ft). Michigan Lake Institute (MLI) stated
that water with less than 90 in (7.5 ft) transparency is considered to be
eutrophic. Significant differences in the transparency (α0.05> 0.015) were
observed in the surface water among the different stations. This was
observed in stations 2 and 5 (α0.05>0.014), 3 and 5 (α0.05>0.034) and in
station 4 and 5 (α0.05>0.046). Station 5 was not directly disturbed by
human’s organic devastation because this area was distant from the
shoreline and the deviation in water transparency could be caused by
suspended matters such as clay, silts and sand obtained in every stations
(Andersson, 2003). By this condition, excessive suspended matters in the
lake will cause water surface to be unclear. If these conditions happen the
light coming from the sun prevent to pass through the water surface that
would decline the photosynthetic rate of the phytoplankton (Boney, 1971).
Chemical Parameters of the Lake Water
The highest amount of dissolved oxygen was obtained at station 4
(10.22±.08mg/L) while lowest at station 1 (8.75±0.05mg/L). Results
showed that there is significant difference (α0.05> 0.009) in the level of
dissolved oxygen among different stations. Station 4 showed significant
differences with station 1 (α0.05>0.006) and 5 (α0.05>0.047) that indicates
the variation in the dissolved oxygen among the stations.
The significant differences of dissolved oxygen in different stations
was due to differences in the stresses that each station obtained. DO
obtained in station 4 was due to reduced amount of stress it receives as
compared with station 1 and 5. On the otherhand, DO obtained from
station 1 maybe due to the human effluents and improper disposal of their
waste in the periphery of lake. Effluents have organic wastes that coming
from the remains of any living organism. It is decomposed by the bacteria
and eventually remove dissolved oxygen from the water when they
breathe. If more food (organic waste) is available for the bacteria, more
bacteria will grow and use oxygen, and the DO concentration will drop
The mean value of dissolved oxygen observed in Sampaloc Lake
was 9.33 mg/L. DO concentration ranging from 9 to 10 mg/L indicated a
very healthy aquatic life (Mack and Cub, 2003). If dissolved oxygen levels
are too low (3-5ppm), some fish and other organisms may not be able to
survive (SIT, 2009). Levels of 5 to 6 ppm are usually required for growth
and activity of aquatic organism (LaMOTTE Company, 2006).
The algal composition of Sampaloc Lake was characterized by three
major groups namely Bacillariophyta, Chlorophyta and Cyanophyta, which
consist of twenty (20) taxa.
Green algae collected was distributed into four (4) orders and six (6)
genera (Figure 3). Five taxa were identified up to the genus level and 1 taxon
was not identified but considered to be in Division Chlorophyta. Moreover, five
(5) orders of Bacillariophyta were collected and it was distributed to eleven
(11) genera (Figure 4-5). In addition, Division Cyanophyta consists of two (2)
orders and three (3) genera (Figure 6).
During the sampling period (November, 2010), 6 genera were determined
under Division Chlorophyta namely Protococcus sp., Pediastrum sp.,
Stigeoclonim sp., Staurastrum sp., Spirogyra sp. and Green Algae 1.
Algae belonging to this group are characterized by green color chloroplast,
one or many in each cell or protoplasmic unit. The cell wall, which is firm in most
genera, is composed of cellulose and pectic compounds. There may be, also, a
mucilaginous outer layer. Sometimes it may be unicellular (one cell), multicellular
(many cells), colonial (living as a loose aggregation of cells) or coenocytic
(composed of one large cell without cross-walls; the cell may be uninucleate or
multinucleate) (Prescott ,1951).
1. Stigeoclonium sp. (Figure 3A)
Thorn-like branches; cell ranges up to 12-18 in diameter.
Branches mostly alternate or opposite; branched filament; cells
scarcely smaller than those or of man’s axis ending in bluntly pointed
or setiferous cell; horizontal or prostrate portion of the thallus often
2. Protoccoccus sp. (Figure 3B)
Simple colony and simple filament; the colony of the cell ranges to
4-6 celled colonies; 1.275 µm in diameter; globular in shaped; cells are
up to 8-12 in diameter.
3. Pediastrum sp. (Figure 3C)
Species form a colony; Shape like a human tooth; the colony of
the cell ranges to 32-38 celled colony; colony cell size is 65µm in
diameter; cells up to 12-20 µm in diameter; thallus flat, circular plate of
polygonal cell; cylindrical cell arranged to form a macroscopic closed
4. Staurastrum sp. (Figure 3D)
Cells appear star shaped or triangular. H-Shaped; cells ranges
to 1.507 µm; apex of cell extended into 3 or more arms or lobes, the
arms usually extended radiantly so that the cell appears star-shaped or
triangular when seen in vertical or end.
5. Spirogyra sp. (Figure 3E)
Filaments are long and unbranched; cell are cylindrical and
short; colony of the cell ranges to 55-90 µm in diameter; 40.8 µm in
length. 20-30 cells diameter. Bright green in color and cotton growth.
6. Green Algae 1 (Figure 3F)
Green algae; non filamentous; the size of the cell ranges 3-
10µm in diameter; semilunate in form; appears to be green.
Figure 3. Different genera of division Chlorophyta (A) Stigeoclonium sp.;(B) Protoccocus sp.;
(C) Pediastrum sp. ; (D) Staurastrum sp.; (E) Spirogyra sp.; (F) Green Algae 1.
During the sampling period (November, 2010) 11 genera were
determined under Division Bacilliariophyta namely Amphora sp., Berkeleya
sp., Cosinodiscus sp. ,Cyclotella sp., Mastoglia sp., Melosira sp., Navicula sp.,
Pinnularia sp., Odontela sp., Nitzcha sp. and Thalossiosira sp.
The external morphology of diatoms is based on the solid silica shell or
frustule that they all have in common. All diatom skeletons are made of silica
and consist of two parts or frustules that fit inside each other like a petri dish:
the epitheca and the hypotheca. The shape of the frustule is the defining
feature that is used to break the diatoms into two distinct classes: the centric
or Centrobacillariophyceae and the pennate or Pennatibacillariophyceae. The
pennate diatoms are usually radially symmetrical while the centric diatoms are
generally bilaterally symmetrical (Alexopoulos, 1967).
7. Nitzchia sp. (Figure 4A)
Frustules solitary; diagonally opposite one another; raphe on a keel
or wing; occur both valves.
8. Cyclotella sp. (Figure 4B)
Cells drum-shaped; the length of the cell size ranges to 0.5-
3µm; valves with an intramarginal zone of costae; frustules circular
in valve view and without spine-like thorns.
9. Coscinodiscus sp. (Figure 4C)
Circular in shaped; species arises up to thousands of cells;
the length of the cell ranges to 30-60µm; valves without intranargint
profusion and every ornament; frustules of drum-shaped,
rectangular in girdle view.
10. Mastoglia sp. (Figure 4D)
Cell is solitary; bean shaped; the length of the cell ranges 1-
5µm; frustules with septa; rectangular in girdle view; naviculated in
valve view; septum large.
11. Melosira sp. (Figure 4E)
Cells closely united to more straight and arranged in
filament; Bread like; short spines at the junction of the frustules,
which are united into a filament; cells ranges to 0.5-1.5µm in
diameter; frustules cylindrical in girdle view attached end to end in
filament polar margin in often with denticulation; with intercalary
Figure 4. Different genera of division Bacillariophyta.(A) Nitzschia sp.; (B) Cyclotella sp. ;
(C) Coscinodiscus sp.; (D) Mastoglia sp.; (E) Melosira sp.; (F) Odontella sp.
12.Odontella sp. (Figure 4F)
Filamentous; cells ranges to 1-2 µm in diameter; colony
composed of 4-6 cells; valves are thin-walled with ocelli on
elevation; mantle rounded.
13.Navicula sp. (Figure 5A)
Cells solitary; cells are longitudinal in form and elongated;
axial field narrow and linear; transverse ornamentation composed
14. Pinnularia sp. (Figure 5B)
Cell is elongated and elliptical; not filamentous; the cell size
ranges to 1-3µm in diameters; composed of 2 valves, valves
overlap like a petri dish; valves are covered by connecting band
15. Thallossiosira sp. (Figure 5C)
Cells in colonies usually wide apart; solitary; the cell size
ranges to 0.5-1µm in diameters; the length of the cell ranges to 1-
Figure 5. Different genera of division Bacillariophyta. (A) Navicula sp.; (B) Pinnularia sp.
(C) Thalasiosira sp.;(D) Amphora sp.;(E) Berkeleya sp..
16.Amphora sp. (Figure 5D)
Comb-like shaped; not filamentous; the cell size ranges to 3-
8 µm in diameter; ventral margin of curved frustules; cells usually
with concave margin.
17. Berkeleya sp. (Figure 5E)
Raphe are straight; the length ranges to 8-25 µm; composed
of 2 cell; cells are long and elongated; optical ending terminate
valves linear-lanceolate, broad with rounded apices.
During the sampling period (November, 2010), 3 genera were determined
under Division Cyanophyta namely Lyngbya sp.,Merismopedia sp.,Oscillatoria
sp..They are characterized by having poorly defined nucleus. Although individual
organisms in this kingdom are for the most part microscopic, their colonies can
reach great size. The cell component lack membrane and the protoplasm is gel-
like without streaming characteristics of eukaryotes. The cell wall are distinct
from those on other algae in consisting of two or more three layers in close
association with the plasma membrane. They are unicellular colonial or
filamentous. The photosynthetic apparatus is not bound in chloroplasts but rather
on the surface of free floating thylakoids (Prescott, 1951).
18.Merismopedia sp. (Figure 6A)
Plate-like colony; quadriangular in cell shaped. 2-4 cells; colony
cells ranges to 15-25 µm in diameter; consisting of more than 4000
cells in one colony; globose cell compactly or loosely arranged in rows
both transverse and longitudinally .
19.Lyngbya sp. (Figure 6B)
Filamentous; diameter of the cell ranges to 1.5-3 µm ; size of the
taxa ranges to 20-50 µm; composed of uniserate and unbranched
trichomes of cell; more or less firm sheath.
20.Oscillatoria sp. (Figure 6C)
Filamentous and elongate; 1-3 µm in cell diameter; solitary or
matted trichomes ; length ranges to 50-80 µm diameter in long; distinct
sheath like membrane the calyptras.
Figure 6. Different genera of division Cyanophyta.(A) Merismopedia sp.; (B) Lyngbya sp.;
(C) Oscillatoria sp
Phytoplankton Community Structure
The composition of phytoplankton community in Sampaloc Lake and
their abundance during November 2010 is presented in Table 2. The algal
composition of Sampaloc Lake was represented by three major groups
namely Bacillariophyta (diatom), Chlorophyta (green-algae) and Cyanophyta
(blue-green algae) which comprises a total of twenty (20) taxa. The taxa were
distributed into 6 genera of green algae, 11 genera of diatoms and 3 genera of
Light microscopy was used to identify the phytoplankton species at high
power magnification. This allowed to identify the morphological characters of
each species. However, the highest possible level of identification is up to
genus level only.
The relative abundance for 3 major phytoplankton groups of Sampaloc
Lake is summarized in Figure 7. The phytoplankton community is highly
represented by Bacillariophyta (55%), Chlorophyta (30%) and Cyanophyta
(15%), respectively. The highest number of taxa was obtained in
Bacillariophyta which accounted for the presence of 11 genera. On the
otherhand, low abundance of Cyanophyta (15%) in the different station of the
lake can be attributed to the impacts of human activities such as household
wastes, manure and industrialized effluents that directly manipulate the
distribution of this group.
Figure 7. Distribution of the major phytoplankton taxa in Sampaloc Lake (November 2010).
Among the five stations, Station 1 had the highest number of taxa
(n=10) while station 4 obtained the least number of taxa (n=4). The difference
is due to the amount of light received by both stations. This circumstance can
cause obstruction of light penetration that is one of the requirements of
phytoplankton to conduct photosynthesis (Boney, 1971). Station 1 was more
likely receiving much light because this area does not have any impediment
such as the presence of trees which station 4 obtained.
During sampling, the dominant taxon was Melosira sp. that can be
found in basic water (Prescott, 1951). It can tolerate at about a pH ranges
from 8 to 9 and accompanied with low transparency (Prescott, 1951 and
Relon, 1988). In this study, results of physico - chemical parameters coincide
with the said condition. Melosira being dominant genera can be a proof that
the water in Sampaloc Lake is in eutrophic condition. Melosira sp. being a
dominant taxa would mean that diatoms respond quickly to environmental
changes as well as for having specific tolerances for water quality (Dixit et al,
Phytoplankters in the five stations with highest frequency (100%) were
observed in Melosira sp. and Cyclotella sp.. Their presence would indicate the
capability of the diatom to adapt to different kinds of environment. With a high
sensitivity to environmental variables, a group of diatoms performs essential
roles that include acting as a primary food source, oxidized the water and
increased the available nutrients (Stone, 2005).
On the otherhand, members of Chlorophyta were found in the lake
specifically Pediastrum sp., Protococcus sp., Spirogyra sp., Staurastrum sp.,
Stigeoclonium sp. and Green Algae 1. It has been reported that the presence
of Pediastrum (18 %) species are more common in eutrophic waters than in
oligotrophic waters (Turkmen, 2005). Therefore, Sampaloc Lake could be
characterized with a eutrophic condition.
Members of Cyanophyta were observed to be more abundant in all
stations except in station 4. Merismopedia sp., Lyngbya sp. and Oscillatoria
sp. belonging to Cyanophyta were observed. These species can tolerate a
polluted water (Turkmen, 2005). Boney (1971) also stated that the presence of
Oscillatoria species on the bodies of water would signify rapid eutrophication.
Characterization of Phytoplankton Community
The summary of diversity indices of the phytoplankton community along
the study site is presented in Table 3. A total of 20 species of phytoplankters
was observed in the study site, where the highest quantity of taxa was found
in station 1 (S=10) whereas the least number was recorded in Station 4
(S=4). Station 1 (D=1.104) showed a high value of species richness as
compared to other stations that is evidently supported by the occurrence of
elevated number of taxa present in the said station. Likewise, low value of
species richness in station 4 (D=0.415) would indicate the low number of taxa
present. The variation between the species richness showed no significant
relationship (α0.05< 1.680) among the different stations. This only shows that
*values are reported as mean ± Standard Error (s/√n)
*values with the same letters are not significantly different at α= 0.05
despite of different stresses that the lake is exhibiting, there would be less
variation in terms of species richness and composition among them.
Moreover, the computed dominance was highest in station 3 (d=0.89)
and lowest in station 1 (d=0.048). The high value of dominance in station 3
indicated that there is a tendency of one (1) species to dominate the
community, which was observed in the abundance of Merismopedia sp. while
dominance(d=0.048) in station 1 would only mean that one (1) taxa will not
strictly dominated the and that was observed in Melosira sp.. Inspite of great
number of cell count in Melosira sp. (2326/ m3
), it shows that abundance in
cell count does not dominate the community as well as with Merismopedia
Hence, high values of Shannon Wienner and Simpson’s Indices were
found in station 2 (H’=1.302; 1-D=0.601) and lowest in station 3 (H’=0.274; 1-
D= 0.11) (Appendix D). Data showed that there were no significant
Taxa Dominance Shannon Simpson Evenness Richness
(S) (d) (H’) (1-D) (E) (D)
1 10 0.048a
2 8 0.398a
3 7 0.890 a
4 4 0.498 a
5 9 0.453 a
Average 20 0.534 0.973 0.466 0.132 1.680
differences between Shannon Wienner Index and Simpson index (H’= α0.05 <
0.384; 1-D = α0.05 < 0.334). This only proved that the overall diversity of the
plankton community is greatly represented by the total quantity of species
present in the area.
Evenness was highest in station 4 (E=0.597). This only means that the
phytoplankton species in station 4 are more evenly distributed than station 3
(E= 0.188). In addition, no significant differences (α0.05 < 0.718) were
observed between species evenness in the different stations. This would
indicate that there is little distribution of phytoplankton in each station.
A total of 20 taxa was documented in Sampaloc Lake during the
sampling period. High species richness (D=1.680) implies that despite the
high dominance value (d=0.534) in the site, there is possibility that one taxon
will dominate the phytoplankton community. Values near one (1) would
indicate that there is a chance of one taxa to dominate the area. Moreover,
values of Simpson Index (1-D=0.466) and Shannon-Wienner Index (0.973)
would indicate that the general diversity of phytoplankton community in
Sampaloc Lake is highly represented by the total quantity of species present
in the study area but index of species evenness (E=0.1324) showed a little
distribution within the community.
SUMMARY, CONCLUSIONS AND RECOMMENDATIONS
Phytoplankton plays an important role in determining the trophic status
of freshwater systems. Their distribution, development and productivity are
directly affected by the varying physical and chemical factors present in an
environment. This study assessed the composition of phytoplankton
community in Sampaloc Lake, San Pablo City, Laguna to qualify the current
water status after the rehabilitation attempt specified by the local government.
Different environmental parameters were measured, specifically
temperature, pH, transparency and dissolved oxygen but only temperature did
not showed significant differences. This may be due to differences in the
stresses experienced by the lake. The values attained from the various
physico-chemical parameters during sampling support the present status of
the lake as eutrophic.
In this study, the composition of phytoplankton community in Sampaloc
Lake was determined as well as their relative abundance and frequencies for
each species identified. The phytoplankton community was highly represented
by Bacillariophyta (55%) followed by Chlorophyta (30%) and Cyanophyta
(15%), respectively. Diversity indices of phytoplankton in Sampaloc Lake were
characterized with high species richness (D=1.682), high dominance
(d=0.534) but uneven(E=0.132) distribution of phytoplankton organisms.
During the sampling period, some species indicated that the Sampaloc
Lake could be eutrophic. This was ascertained by the dominance of Melosira
sp., which can also tolerate about pH 8 and low transparency of water.
Merismopedia sp., Lyngbya sp. and Oscillatoria sp. (Cyanophyta) also
indicated polluted water and rapid eutrophication.
Based on the results obtained, the following conclusions were figured
1. the phytoplankton community in Sampaloc Lake was distributed to 3 major
groups namely Division Chlorophyta, Bacillariophyta and Cyanophyta ;
2. a total of 20 taxa was present in Sampaloc Lake and dominated by
Melosira sp. ; and
3. Sampaloc Lake is exhibiting eutrophic condition based on the presence of
Upon completion of the study, the following are recommended:
1. the trophic state of Sampaloc Lake be verified using other chemical
2. continuous monitoring of the lake be done to improve the trophic
condition of the lake; and
3. use (scanning electron microscope) SEM in identification of the
phytoplankton at species level.
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Nautical Map of San Pablo City Laguna
Description of San Pablo City, Laguna
San Pablo City, Laguna's first city, is an important commercial and
transportation hub linking the provinces of Laguna with Batangas and Quezon
and is also on the southern rail line. San Pablo City is also known as the “City of
the Seven Lakes.” There are actually 8 crater lakes of extinct volcanoes
(including a very small one), each nestled in a depression created long ago by
volcanic activity. All have scenic charm and are worth seeing. Total aggregate
area is 210 hectares. The other lakes have an aggregate area of 34 hectares.
The seven lakes are Sampaloc Lake, Calibato Lake, Bunot Lake, Mohicap Lake,
Palakpakin Lake, Lake Pandin and Lake Yambo.
Lake Sampaloc is an inactive volcanic maar on the city. The 105-hectare
Sampaloc Lake is the largest of the city's lakes. It is also the most accessible
being just in the vicinity of the City Hall.
Considered one of the prime tourist spots in the city, Sampalok Lake is
also home to numerous floating restaurants along its shoreline that serve Filipino
food and Native Philippine cuisine. It used to abound with various types of fish
tilapia, bangus, carp and several species of shrimps but not anymore. Today the
fishpens in the lake are for growing fingerlings only.
San Pablo City is 2 hours drive from Makati. It is a border city to the
province of Quezon where the nearby town Tiaong has the storied Villa Escudero
resort. Most of the bus lines servicing Laguna and Southern Luzon will have
direct trips to San Pablo. Also, Lucena-bound buses pass through the city limits.
Preparation of 3% buffered formalin
The preserving solution (3% buffered formalin) was prepared by adding 54
mL (37%) of commercial formalin for every one liter and saturated with borax
powder. This type of preservative affected the color and avoids the deformation
of the cell (Azanza – Corrales, 1993).
Table for Analysis of Variance (ANOVA)
C.1 Analysis of Variance of Physico-chemical Parameters of Phytoplankton Community.
Parameters F p-value
Temperature 2.717 0.091
pH 5.288 0.015
Transparency 5.302 0.015
Dissolved Oxygen 6.283 0.009
C.1.1 Multiple Comparison of the Different Environmental Factors of Phytoplankton using Tukey HSD.
Temperature pH Transparency Dissolved
1 2 0.982 0.908 0.364 0.589
3 0.925 0.662 0.657 0.103
4 0.075 0.238 0.765 0.006
5 0.641 0.372 0.266 0.664
2 1 0.982 0.908 0.364 0.589
3 0.999 0.984 0.979 0.679
4 0.166 0.067 0.939 0.058
5 0.901 0.824 0.014 1.000
3 1 0.925 0.662 0.657 0.103
2 0.999 0.984 0.979 0.679
4 0.244 0.030 1.000 0.391
5 0.972 0.980 0.034 0.605
4 1 0.075 0.238 0.765 0.006
2 0.166 0.067 0.939 0.058
3 0.244 0.030 1.000 0.391
5 0.512 0.013 0.046 0.047
5 1 0.641 0.372 0.266 0.664
2 0.901 0.824 0.014 1.000
3 0.972 0.980 0.034 0.605
4 0.512 0.013 0.046 0.047
C.2 Analysis of variance for the diversity indices
Diversity Indices F Sig. (0.05)